Over-the-water docks are able to service a greater volume and variety of marine craft compared to docks built along a shoreline. Originally, over-the-water docks were made of timber fixed to sunken pilings driven into the lake or seabed. However, the constant exposure to water and weather lead to rapid deterioration and significantly increased the costs of maintenance and repair.
Floating docks evolved as one solution for providing cost effective over-the-water marine docks. Floating docks utilize buoyant floats over which a deck surface is built. The service life of the dock, though, is closely tied to the continuity of the floats. A loss of watertight integrity can compromise freeboard and lead to eventual dock failure.
Conventional buoyant floats vary in their efficacy. For instance, foam-encapsulated concrete floats rely on rigid shells to preserve the concrete's structural soundness, but such shells are susceptible to cracking due to temperature extremes, which leads to water seepage and eventual failure. Patching provides only a temporary and generally unsatisfactory solution. Further, rebar-reinforced concrete is vulnerable to rust upon exposure to moisture, resulting in irreparable internal weakening. Alternatively, foam-filled rubber tires can function as inexpensive floats, but can suffer from rubber deterioration. Polyethylene foam-filled floats avoid these shortcomings by providing low maintenance expense and long service life.
In general, float repair or replacement often requires the dismantling of an entire dock. One popular floating dock design, such as disclosed in U.S. Pat. No. 4,365,914, to Sluys, utilizes longitudinal wooden walers held against captive floats by transverse tension bars. The tension bars tend to loosen over time as temperature and humidity act on the walers. Moreover, waler replacement entails complete dock dismantling due to the interdependence of floats, decking, walers, and tension rods, which involves significant cost and repair time.
Over-the water docks can adversely affect shoreline marine life by blocking sunlight from submerged vegetation and shallow dwelling creatures. Conventional floating docks inadequately permit light-through, which frequently is provided by ad hoc design. Provisionings for light penetration are irregular and occur by happenstance where dock construction permits, such as with staggered float placement or on top of walers having sufficient uninterrupted run.